Surface characterization of electrochemically formed passive film on nitrogen ion implanted Ti6Al4V alloy

Nitrogen ion implantation was carried out to modify the surface of a Ti6Al4V alloy for improving its corrosion resistance in a simulated body fluid environment. Ion implantation was carried out at 70 keV energy at the dose of 7x10(20) ions/m(2). The implanted surface was electrochemically passivated at 1.0 V for 1 h. X-ray photoelectron spectroscopy (XPS) was used to identify the concentration and chemical state of the elements present in the passivated film. The change in the nature and composition of the passive Nm of the implanted-passivated specimen was compared with the unimplanted-passivated and as-implanted specimens. Open Circuit Potential (OCP)-time measurement and cyclic polarization studies were additionally carried out to understand the nature of the passive film. The results showed that the implanted specimen exhibited enhanced corrosion resistance than the unimplanted specimen (one order of magnitude) due to the presence of oxynitride along with oxide in the passive film.